1. Field of the Invention
The present invention relates to an auto-lock style continuity test unit, and more specifically relates to continuity testing for automobile wire harnesses, testing of sub-assemblies (hereinafter referred to as "wire assembly") including a wire harness, or testing between electrical devices.
2. Description of the Related Art
The wire assembly is, in general, an electrical wiring system which forms a predetermined circuit in connection with a plurality of wires. Terminal fittings, which include a male or female type connected with each electric wire, are incorporated in a connector housing, and are protected by a so-called lance type non-slip element. By connecting a connector housing which incorporate a male terminal fitting with one which incorporates a female terminal fitting, electrical connection is achieved between both terminal fittings. The terminal fittings mentioned above are not permitted to slip off from the connector housing with the external force normally applied during use or to encounter a nonconductive failure. Thus, continuity test units have conventionally been proposed to test the electrical continuity or mechanical standstill condition of terminal fittings incorporated in the connector housing.
The continuity test units heretofore proposed have been provided with a housing holder which retains a connector housing, and a test device which carries probe pins to contact the terminal fittings in the retained connector housing. In this case, among the above-mentioned probe pins, a so-called 2 probe-form (which has a switch function and is well known in the art) incorporates a spring member having a capacity allowing a comparatively larger load so as to push off a terminal fitting which is incorrectly loaded into the connector housing, and to allow electrical continuity to be achieved as long as this spring member is deflected a certain distance.
The above-mentioned housing holder and test device are mutually constructed so as to be relatively movable, and the probe pins are brought into contact with the terminal fittings by relatively moving the housing holder and check device using a manual lever, such as a toggle lever.
However, moving the housing holder and test device using a manual lever is undesirable due to poor workability and because it is labor intensive. That being the case, currently so-called auto-lock continuity test units, similar to the invention disclosed below, are mainly proposed which allow continuity testing by positioning a connector housing on probe pins by merely inserting the connector housing to be checked. (See, for example, Japanese Patent Publications (Unexamined) HEI 5288792 and U.S. Pat. No. 5,498,966.)
The structure comprises a connector insertion area for inserting a connector housing to be checked, probe pins mounted inside the connector insertion area, and a connecting tool for connecting the back of the inserted connector, and is arranged to allow the connector to fasten to the connector insertion area by shifting the above-mentioned connecting tool in a direction across the axial direction of the connector at a certain time.
With the above-mentioned prior art, since the probe pins were directly mounted on a connector insertion area, there was a limitation to an adaptable probe pin. That is, provided a 2 probe-form pin as mentioned above was adopted, it was necessary to push the connector housing with the worker's finger force against the control force of a spring member which is provided for the probe pins in case of mounting the connector housing into the connector insertion area. But, since the force required for deflecting a spring member of the probe pins is normally more than 4 kgf, there was the inconvenience of not to be able to insert the connector housing into a connector insertion area with normal worker's finger for such work which required a greater burden on workers.
The present invention was made to overcome the above-mentioned inconvenience, and the object is to provide an auto-lock type continuity test unit not limited to a few probe pins.